Tandem pump



Dec. 26, 1961 W- DOBLE I 3,014,429

TANDEM PUMP Filed Jan. l5, 1959 ,FZ/mix ,d2 fla fell l a R /S-@f/ WJ 031.5, 44 Je f2 REN ffENToR.

States .iabseo Pump Company, Costa Mesa, Calif., a corporation of California Filed Jan. l5, 1959, Ser. No. '737,028 6 Claims. (Cl. 10S-4) The present invention relates in general to pumps and, more particularly, to pumps having impellers provided with elastomeric radial varies which are flexed by cams in the impeller bores of the pumps, in response to rotation of the impellers, to pump fluid from inlets leading into the impeller bores to outlets leading therefrom.

Still more particularly, the invention relates to a dual or tandem pump which includes two coaxial impellers respectively disposed in two coaxial impeller bores and driven by a common shaft, a pump of this nature being disclosed in co-pending patent application Serial No. 611,540, led September 24, 1956, by James R. Walsh, Nils Hanson and me, now abandoned. In such a tandem pump, the two impeller bores are separated by an annular partition which is disposed between the two impellers and between the two cams which flex the elastomeric vanes of the two impellers, such annular partition being pinned to the cams to prevent rotation thereof as the result of frictional engagement therewith by the two impellcrs.

` The foregoing prior construction suffers from the disadvantage that friction between the annular partition and the two impellers subjects the annular partition to a force couple one component of which is resisted by the pinned connection between the annular partition and the cams and the other component of which is resisted by the housing of the pump, this latter component being the result of the tendency of the annular partition to pivot about the pinned connection to the cams as the impellers rotate. In operation of such a prior pump, the component of the force couple which is resisted by the housing frequently wears a slot in the housing to cause leakage between the two impeller bores. Also, the component of the force couple which is resisted by the pinned connection sometimes shears this connection with the result that the annular partition rotates with the. impeller and cuts its way into, or even through, the housing since the annular partition is not restrained to rotate only about the axis of impeller rotation under such conditions, but can be deflected laterally as the result of the pumping pressure.

A primary object of the present invention is to eliminate the foregoing disadvantages of prior tandem pumps by making the annular partition rotatable with the impellers and by providing means for rotating the annular partition concurrently with the impellers about the axis of impeller rotation. In other words, a primary object of the invention is to provide means for rotating the annular partition and for restraining it to rotate solely about the axis of impeller rotation so that.l it cannot score the housmg.

The annular partition may, in accordance with the presentvinvention, be made rigid, as bymaking it of metal,

or it may be elastomeric, other objects of the invention being to provide partitions of this nature.

atent The foregoing objects, advantages,. features and results ice FIG. 2 is a transverse sectional view taken along the arrowed line 22 of FIG. 1;

FIG. 3 is a perspective view of an annular partition incorporated in the embodiment illustrated in FIGS. l and 2; and

FIG. 4 is a fragmentary longitudinal sectional View of another tandem pump embodiment of the invention.

Referring to FIGS. l to 3 of the drawing, the numeral 10 designates a housing which is provided therein with axially aligned rst and second impeller bores 12 and 14. The housing lll is also provided with a lirst inlet lr6 and a first outlet 18 which communicate with the iirst irnpeller bore 12 and which are spaced apart circumferentially thereof. The housing is provided with a second inlet and a second outlet, not shown, which are spaced apart circumferentially of and communicate with the second impeller bore i4.

Disposed in the rst impeller bore 12 and secured therein by a screw 20 is a Iirst cam 22 which is disposed between and overlaps the first inlet 16 and the first outlet 18, this cam being provided with openings 24 and 26 therethrough respectively registering with the first inlet and the first outlet. Axially aligned with and axially spaced from the lirst cam 22 is a second cam 28 disposed in the second impeller bore 14 and secured by a screw 30, the second cam having the same relation to the second inlet and the second outlet as the first cam does to the first inlet 16 and the first outlet 18.

Disposed in and coaxial with the impeller bores 12 and 14 is a shaft 32 which projects through an end wall 34 of the housing 1d for connection to an external drive means, not shown, the other end wall of the housing being formed by a removable cover plate 36. Leakage from the interior of the housing and along the shaft 32 is prevented by a shaft seal 3S encircled and engaged by an O-ring 40 disposed in an annular groove in the end wall 34 of the housing 10. To prevent wear of the end wall 34 of the housing 10, this end wall is faced by a wear plate 42 which may be rigidly secured to the housing in any suitable manner, not shown. The cover plate 36 serves as a wear plate for the other end of the housing 1).

Respectively disposed in the first and second impeller bores 12 and 14 in axial alignment and in axially spaced relation are first and second elastomeric impellers 44 and 46, the impeller 44 having an end in engagement with the cover plate 36 and the impeller 416 having an end in engagement with the Wear plate 4Z. The first and second impellers 44 and 46 respectively have first and second hubs 48 and 50 which are suitably fixed on the shaft 32 so as to be rotatable therewith. In the construction illustrated, inserts 52 and 54. are embedded in the first and second hubs 4S and 50, respectively, and are internally splined for engagement with externally splined portions S6 and 58, respectively, of the shaft. 'Ihe lirst and second impellers 44 and 46 respectively include elastomeric radial vanes 6l) and 62 which are flexed by the first and second cams 22 and 28, respectively, to produce the pumping action characteristic of pumps of this type.

The impeller bores 12 and 14 are separated by an annular partition or divider 64 which is disposed between the first and second impellers 44 and 46 and between the first and second cams 2v2 and 21S. The annular partition 64 is provided onl opposite sides thereof adjacent its inner periphery with cylindrical axial bosses 66 and 618 which irietionally engage the peripheral walls of cylindrical axial recesses 70 and 72,.respectively, in the adjacent ends of the first and second hubs 48 and Sit, the bosses 66 and 618 being annular `flanges in the construction illustrated.

V The annular partition 64 may be a rigid member formed of metal, or similar material. Howe-ver, it may also be formed of an elastomeric material similar to that utilized for the first and second impellers 44 and 46 if desired.

With the foregoing construction, friction between the first and second impellers 44 and 46 and the annular partition 64 results in rotation of such partition with the impellers as the latter are rotated by the shaft 32. Pr viding the annular partition with the cylindrical bosses 66 and 68 disposed in the completementary receses 70 and 72 in the impeller huos 4S and 50` insures that such rotation of the annular partition Will 1be about the axis of the shaft 32. Consequently, the external periphery of the annular partition 64, which is spaced from the housing by a few thousandths of an inch to provide a running clearance, cannot score the housing. Thus, since the annular partition 64 is free to rotate and since it is constrained to rotate solely about the axis of the shaft 32, the hereinbefore-discussed disadvantages of prior tandem pumps wherein the annular partition is pinned in position are avoided.

Whenever it is necessary to remove the internal parts of the dual pump of the invention for repair or replacement, this may be accomplished readily by removing the cover plate 36 and the screws 20 and 30, whereupon the first impeller and cam 44 and 22, the annular partition 64, the second impeller and cam 46 and 28, the wear plate 42, the shaft seal 38 and the O-ring 4G may all be removed.

Referring to the embodiment of the invention illustrated in FIG. 4 of the drawing, the various parts of this ernbcdiment are designated by numerals higher by l0() than the numerals used to designate the corresponding parts of the embodiment of FIGS. l to 3. The embodiment of FIG. 4 differs from that described previously in that the shaft 132 is provided with a single externally splined portion 174 which engages both the internally splined inserts 152 and 154 and also engages an annular partition 164 which is internally splined. With this construction, the splined connection between the annular partition 164 and the sha-ft 132 both rotates the partition 164 and constrains it to rotate about the `axis of the shaft so that no scoring of he housing 110 can result.

Although exemplary embodiments of the invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claims which follow.

I claim:

1. In a tandem pump, the combination of: a housing provided with axially aligned first and second impeller bores, said housing being provided with first and second inlets respectively communicating with said first and second impeller bores, and said housing being provided with first and second outlets respectively spaced circumferentially from said first and second inlets and respectively communicating with said first and second impeller bores; axially aligned, axially spaced, first and second cams respectively disposed in said first and second impeller bores, said first cam being disposed between said first inlet and said first outlet and said second cam being disposed between said second inlet and said second outlet; a shaft in said first and second impeller bores, said shaft being coaxial with and rotatable about the axis of said impeller bores and projecting from one end of said housing; axially aligned, axially spaced, first and second irnpellers respectively disposed in said first and second irnpeller bores and respectively having first and second hubs fixed on said shaft, said first and second impellers respectively having first and second elastomeric vanes respectively engageable with said first and second cams; an annular partition in said housing and encircling said shaft between said first and second cams and between said first and second impellers, said partition being concentric with and separating said first and second impeller bores; and partition mounting means spaced radially inwardly from said housing for rotating said annular partition about said axis concurrently with said shaft and said first and second impellers and for preventing lateral movement of said annular partition relative to said axis.

2. A tandem pump according to claim l wherein said partition mounting means comprises means for connecting said annular partition to said shaft.

3. In a tandem pump, the combination of: a housing provided with axially aligned first and second impeller bores, said housing being provided with first and second inlets respectively communicating with said first and sccond impeller bores, and said housing being provided with first and second outlets respectively spaced circumferentially from said first and second inlets and respectively communicating with said first and second impeller bores; axially aligned, axially spaced, first and second cams respectively disposed in said first and second impeller bores, said first cam being disposed between said first inlet and said first outlet and said second cam being disposed between said second inlet and said second outlet; a shaft in said first and second impeller bores, said shaft being coaxial with and rotatable about the axis of said impeller bores and projecting from one end of said housing; axially aligned, axially spaced, first and second impellers respectively disposed in said first and second impeller bores and respectively having first and second hubs fixed on said shaft, said first and second impellers respectively having first and second elastomeric vanas respectively engageable with said first and second cams; an annular partition in said housing and encircling said shaft be tween said first and second cams and between said first and second impellers, said partition being concentric with and separating said first and second impeller bores; and means connecting said partition to said first and second hubs for rotating said annular partition about said axis concurrently with said shaft and said first and second impellers and for preventing lateral movement of said annular partition relative to said axis.

4. In a tandem pump, the combination of: a housing provided with axially aligned first and second impeller bores, said housing being provided with first and second inlets respectively communicating with said first and second impeller bores, and said housing being provided with first and second outlets respectively spaced circumferentially from said first and second inlets and respectively communicating with said first and second impeller bores; axially aligned, axially spaced first and second cams respectively disposed in said first and second impeller bores, said first cam being disposed between said first inlet and said first outlet and said second cam being disposed between said second inlet and said second outlet; a shaft in said first and second impeller bores, said shaft being coaxial with and rotatable about the axis of said impeller bores and projecting from one end of said housing, axially aligned, axially spaced, first and second impellers respectively disposed in said first and second impeller bores and respectively having first and second hubs fixed on said shaft, said first and second impellers respectively having first and second elastomeric vanes respectively engageable with said first and second cams, adjacent ends of said first and second hubs being provided therein with cylindrical vaxial recesses; and a rotatable annuular partition in said housing between said first and second cams and between said first and second impellers, said annular partition being concentric with and separating said first and second impeller bores and being provided on opposite sides thereof with cylindrical axial bosses respectively disposed in said recesses, said bosses and said impeller hubs cooperating to maintain said annular partition coaxial Vwith said shaft and to transmit rotation of said impeller hubs about said axis to said annular partition.

S. In a tandem pump, the combination of: a housing provided with axial aligned first and second impeller bores, said housing being provided with first and second inlets respectively communicating with said first and sec- 0nd impeller bores, and said housing being provided with first and second outlets respectively spaced circumferentially from said first and second inlets and respectively communicating with said first and second impeller bores; axially aligned, axially spaced, first and second cams respectively disposed in said first and second impeller bores, said first cam being disposed between said first inlet and said first outlet and said second cam being disposed between said second inlet and said second outlet; a shaft in said first and second impeller bores, sai dshaft being coaxial with and rotatable about the axis of said impeller bores and projecting from `one end of said housing; axially aligned, axially spaced, first and second impellers respectively disposed in said first and second impeller bores and respectively having first and second hubs fixed on said shaft, said first and second impellers respectively having first and second elastomeric varies respectively engageable with said first and second cams; an annular partition in said housing and encircling said shaft between said first and second cams and between said first and second impellers, said partition being concentric with and separating said first and second impeller bores, said annular partition being rigid; and partition mounting means spaced radially inwardly from said housing for rotating said annular partition about said axis concurrently with said shaft and said first and second impellers and for preventing lateral movement of said annular partition relative to said axis.

6. In Aa tandem pump, the combination of: a housing provided with axially aligned first and second impeller bores, said housing being provided with first and second inlets respectively communicating with said first and second impeller bores, and said housing being provided with first and second outlets respectively spaced circumferentially from said first and second inlets and respectively communicating with said first and second impeller bores;

axially aligned, axially spaced, first and second cams respectively disposed in said first and second impeller bores, said first cam being `disposed between said first inlet and said first outlet and said second cam being disposed between said second inlet and said second outlet; a shaft in said first and second impeller bores, said shaft being coaxial with and rotatable about the axis of said impeller bores and projecting from one end of said housing; axially aligned, axially spaced, first and second impellers respectively disposed in said first and second impeller bores and respectively having first and second hubs fixed on said shaft, said first an dsecond impellers respectively having first and second elastomeric vanes respectively engageable with said first and second cams; an annular partition in said housing and encircling said shaft between said first and second cams and between said first and second impellers, said partition being concentric with and separating said first and second impeller bores, said annular partition being elastomeric; and partition mounting means spaced radially inwardly from said housing for rotating said annular partition about said axis concurrently with said shaft and said first and second impellers and for preventing lateral movement of said annular partition relative to said axis.

References Cited in the file of this patent UNITED STATES PATENTS 2,490,115 Clarke Dec. 6, 1949 2,499,163 Rand Feb. 28, 1950 2,531,808 Eames Nov. 28, 1950 2,573,819 Weyer Nov. 6, 1951 2,855,853 Yaughter et al. Oct. 14, 1958 2,856,859 Baade et a1 Oct. 21, 1958 

